More than 2% of our children are considered to be mentally
retarded.
In order to understand retardation, we need to look a little at the
concept
of intelligence. We define intelligence as "general cognitive
ability,"
meaning how well a person can solve problems, how easily they learn new
things,
and how quickly they can see relationships among things.

Intelligence Quotient (IQ) is the score you get on an intelligence
test. Originally, it was a quotient (a ratio): IQ= MA/CA x
100, where MA is
mental age and CA is chronological age. So a child who is 10 and
has
the same level of intellectual ability as most 10 year olds has an IQ
of
10/10 x 100 = 100. If that 10 year old has the same ability as a
15
year old, his IQ will be 15/10 x 100 = 150 (very smart indeed).
If
the 10 year old has the ability of a 5 year old, his IQ would be 5/10 x
100
= 50, which is considered mentally retarded.

Nowadays, IQ is a matter of comparing a person with many others of
the same age, and assigning a score based on their place on a normal
curve:

Here you get to see several important points about not only IQ but
about descriptive statistics.

1. The normal curve, also called the bell-shaped curve, is an idealized
version of what happens in many large sets of measurements: Most
measurements
fall in the middle, and fewer fall at points farther away from the
middle.
Here, most people score near 100 (the average), and much fewer people
score
very high or very low.

2. The mean is just the average of all scores.
The sum
of everyone’s IQ scores, divided by the number of scores, is the mean,
which
was originally set at 100. That has become the tradition.

3. The standard deviation (sd). The standard
deviation is like the average degree to which scores deviate from the
mean. For
our purposes, just know that 1 standard deviation above and below the
mean
contains (in an ideal normal curve!) 68% of all the scores, 2 standard
deviations
contain 95.6%, and 3 standard deviations contain 99.7%. Or, you
could
say that there are only 2.2% above 130 and 2.2% below 70, and so
on.
By tradition, one standard deviation is 15 points. The
percentages
you see in the normal curve above are based on 10 point spreads:
10
points above or below the mean (90 to 110) contains 50% of all the
scores.

The names for various "smart" people are of relatively little
importance to us. But the differences among retarded people can
be very significant.
Please understand that the ranges are approximations, and
labeling
people is always a difficult and dangerous thing!

An interesting question to ask is: If being below, say, 50 is
due
to "brain damage," what do we say about people above, say, 150?
Are
they "brain enhanced?" Or do they have a different, more
beneficial
sort of "brain damage?"

Autism

Autism, the most common of the pervasive developmental
disorders (with a prevalence of 10 to 12 children per 10,000 [Bryson
& Smith, 1998]),
is characterized by severely compromised ability to engage in, and by a
lack
of interest in, social interactions. It has roots in both structural
brain
abnormalities and genetic predispositions, according to family studies
and
studies of brain anatomy. The search for genes that predispose to
autism
is considered an extremely high research priority for the National
Institute
of Mental Health (NIMH, 1998). Although the reported association
between
autism and obstetrical hazard may be due to genetic factors (Bailey et
al.,
1995), there is evidence that several different causes of toxic or
infectious
damage to the central nervous system during early development also may
contribute
to autism. Autism has been reported in children with fetal alcohol
syndrome
(Aronson et al., 1997), in children who were infected with rubella
during
pregnancy (Chess et al., 1978), and in children whose mothers took a
variety
of medications that are known to damage the fetus (Williams &
Hersh,
1997)

The causes of autism are still not known. It is believed by
most
researchers that it involves problems with neural circuits, and twin
studies
suggest that genetic influences are likely. For a long time, it
was
assumed incorrectly that autism resulted from parental neglect.

Because autism is a severe, chronic developmental
disorder, which results in significant lifelong disability, the goal of
treatment is
to promote the child’s social and language development and minimize
behaviors
that interfere with the child’s functioning and learning. Intensive,
sustained
special education programs and behavior therapy early in life can
increase
the ability of the child with autism to acquire language and ability to
learn.
Special education programs in highly structured environments appear to
help
the child acquire self-care, social, and job skills.

There has been some limited success with antipsychotic drugs and
with
antidepressants.

In the last 20 years or so, a number of finer differentiations have
evolved
regarding what is now seen as an autistic spectrum. First,
we
have something called Asperger's Syndrome. These children
(and
adults) are generally of normal (and sometimes high) intelligence, but
have
difficulty in social interaction. They seem exceptionally shy and
have
a hard time making eye contact. They have trouble learning
what
is called pragmatics - the
part of communication between people that
involves
recognizing turn-taking, facial expressions, gestures, and other
non-verbal
cues. They tend to focus intensely on one thing at a time, don't
like
abrupt changes, and develop obsessive routines. As adults, they
usually
adapt, but are seen as being socially inept, absent minded, and
eccentric.
Of course, that begs the question a little: Is this truly a
separate
disorder, or just a little out there on the continuum of normal
behavior? I think you can tell that some of your professors may
be Asperger's people.

There are other syndromes that focus more on language: The semantic-pragmatic
disorder is sometimes used to label certain children who are
similar
to Asperger's children but more sociable. The focus of their
problem
is more on the communications side.

Hyperlexia is more a symptom than a disorder. It is a
matter
of being rather precocious in reading words, and being fascinated by
letters
and numbers. On the other hand, children with hyperlexia don't
communicate
well, nor do they socialize well.

Non-verbal learning disability is a matter of having a hard
time
with visual, spatial, and motor skills. They have a hard time
picking
out, say, one house out of a row of them, tying their shoes, getting
dressed,
kicking a ball, reading facial expressions, and recognizing the tone of
someone's
voice. One of the notable symptoms is the tendency to stare,
especially
when visually over-stimulated.

A related problem that is close to my heart (because I have a mild
version
of this) is prosopagnosia
or face blindness. This affects about 2 1/2 % of the population,
and people with
this
problem have a difficult time recognizing faces. It can be so
severe
that a man can walk past his own mother and not recognize her!
Generally,
people with this problem develop other ways of recognizing people, such
as
clothing or hair styles. I recognize people I have known for a
long
time, but cannot place less familiar people out of the context
of,
say, a specific classroom or circumstance. It makes one seem
rude,
but it is unintentional. I deal with it by simply saying hello to
everybody. Interestingly, people with prosopagnosia
often also have a hard time identifying some other things, such as dogs
and cars! It is believed to be a problem involving the fusiform
gyrus, which is involved in facial recognition.

Learning Disorders

We say a child has a learning disorder when his or her performance
is significantly
below his or her IQ, i.e. they are not learning "up to their
potential."
We estimate that about 5% of students in US public schools have a
learning
disorder. Learning disorders are
often
found accompanying other medical problems such as lead poisoning, fetal
alcohol
syndrome, and so on.

Reading disorder - better known as dyslexia - is
the most
common learning disorder. Here, the child's reading scores are
significantly
below their IQ, their expected age level, or their general
abilities. These
kids
seem to have trouble with the usual left to right scanning of words,
which
leads them to reverse letters and jumble the spelling. It could
be
compared
to trying to read a newspaper in a language you have little familiarity
with.

It is estimated that about 4% of US school kids have dyslexia.
60
to 80% of those diagnosed are boys, but this may be a matter of
identification: boys with reading disorder act up more, drawing
attention to their problems, while the girls tend to be quieter and
less trouble. This is, of course,
a problem for the girls in that their dyslexia is less often caught
early.

Helping children with learning disorders has become a big part of
educational research. Basically the help involves slow, careful
teaching that gives
the child an opportunity to work without the pressures of competition
and
frustration that exist in the ordinary classroom setting. In
England,
they take a different attitude towards dyslexia, seeing it as more a
maturational
problem rather than a more permanent neurological condition.

It should also be noted that dyslexia is a far greater problem for
children who speak English than other languages: Of all languages
written with
a western alphabet, English has the most inconsistent spelling.
Spelling is
not even a subject in most western languages, because words are spelled
pretty
much as they sound! Unfortunately, there are few signs that
English-speaking
people will ever change their spelling system. Too bad.

Attention-Deficit/Hyperactivity Disorder

ADHD is really two different problems - inattentiveness and
hyperactivity-- that nevertheless often go together. It has
been the focus of a
great deal of controversy. Opinions range from considering ADHD
to
be a purely physical, highly genetic, medical problem to the belief
that
it is nothing more than the differences between children's maturation
rates.
Here are the opinions offered by the Surgeon General’s report:

Inattention or attention deficit may not become apparent
until
a child enters the challenging environment of elementary school. Such
children
then have difficulty paying attention to details and are easily
distracted
by other events that are occurring at the same time; they find it
difficult
and unpleasant to finish their schoolwork; they put off anything that
requires
a sustained mental effort; they are prone to make careless mistakes,
and
are disorganized, losing their school books and assignments; they
appear
not to listen when spoken to and often fail to follow through on tasks
(DSM-IV;
Waslick & Greenhill, 1997).

The symptoms of hyperactivity may be apparent in very young
preschoolers and are nearly always present before the age of 7
(Halperin et al., 1993; Waslick & Greenhill, 1997). Such symptoms
include fidgeting, squirming around when seated, and having to get up
frequently to walk or run around. Hyperactive children have difficulty
playing quietly, and they may talk excessively.
They often behave in an inappropriate and uninhibited way, blurting out
answers
in class before the teacher’s question has been completed, not waiting
their
turn, and interrupting often or intruding on others’ conversations or
games
(Waslick & Greenhill, 1997).

Many of these symptoms occur from time to time in normal
children. However, in children with ADHD they occur very frequently and
in several settings,
at home and at school, or when visiting with friends, and they
interfere
with the child’s functioning. Children suffering from ADHD may perform
poorly
at school; they may be unpopular with their peers, if other children
perceive
them as being unusual or a nuisance; and their behavior can present
significant
challenges for parents, leading some to be overly harsh (DSM-IV).

Inattention tends to persist through childhood and adolescence
into adulthood, while the symptoms of motor hyperactivity and
impulsivity tend to diminish with age. Many children with ADHD develop
learning difficulties that may not improve with treatment (Mannuzza et
al., 1993). Hyperactive behavior
is often associated with the development of other disruptive disorders,
particularly
conduct and oppositional-defiant disorder (see Disruptive Disorders).
The
reason for the relationship is not known. Some believe that the
impulsivity
and heedlessness associated with ADHD interfere with social learning or
with
close social bonds with parents in a way that predisposes to the
development
of behavior disorders (Barkley, 1998).

Even though a great many children with this disorder ultimately
adjust (Mannuzza et al., 1998), some—especially those with an
associated conduct or oppositional-defiant disorder—are more likely to
drop out of school and
fare more poorly in their later careers than children without ADHD. As
they
grow older, some teens who have had severe ADHD since middle childhood
experience
periods of anxiety or depression. This seems to be especially common in
children
whose predominant symptom is inattention (Morgan et al., 1996)....

We don’t have any solid knowledge about the origins of ADHD, but it
is
believed to include some very basic genetic, prenatal, and
neurotransmitter problems. It is thought that children with ADHD
do not have enough dopamine - a neurotransmitter that has a lot to do
with controlling behavior -
in
their nervous system. It does seem to run in families, so a
genetic
factor is quite possible. And ADHD occurs more often in children
from
mothers
who smoked while pregnant, in children exposed to lead, and in children
who
suffered from anoxia (low oxygen) during birth.
(Whittaker
et al., 1997).

Treatment of children with ADHD usually involves two
approaches: Medication and behavioral training. The
behaviorial training involves the parents as much as the child, and
usually includes finding the appropriate ways of rewarding and
punishing the child, including rewarding with attention and using the
famous
“time-out” approach to discipline.

Medication takes the form of amphetamines and amphetamine-like
stimulants such as Ritalin. Research shows that
stimulants are effective
in 75 to 90% of all ADHD children (Spencer et al., 1995; Greenhill,
1998a,
1998b; Greenhill et al., 1998). Many peple have expressed some
concern
that we are overdiagnosing and overmedicating children, and that
Ritalin
is just a way teachers and parents get rid of annoying kids. But
there
is, in fact, little evidence of this (Goldman et al., 1998; Jensen et
al.,
1999).

All this said, it should nevertheless be noted that some researchers
see
ADHD as a false category, and the use of stimulants akin to the way in
which
cocaine (or coffee) makes the average person temporarily more creative
and
productive. In fact, coffee has been used with some success in
helping
ADHD kids!

Stuttering, Tics, and Tourette's Syndrome

There are a number of problems kids face that involve neuromotor
dysfunction. One of the most common is stuttering, which
is found in about 1% of
all children. It is found 3 times more commonly in boys.
The
good new is that 60% of stutterers recover on their own, usually by the
age
of 16. With the help of speech therapists, another 20% recover as
well.
Stuttering is strongly connected to anxiety, and it often disappears
when
the child is relaxed or, for example, when they are singing!

Somewhat more problematic are tics, which are repetitive
abnormal movements that cannot be controlled. Most of us think of
facial tics - a repetitive squint or upward jerk of the cheek and so
on. But some
tics are far more dramatic. For example, there are various
twisting
movements, where the person's arm moves out like a snake, or dancing
movements
involving the whole body, even sudden deep knee
bends.
Like stuttering, tics are strongly associated with anxiety and therapy
often
concentrates on developing a relaxed attitude that diminishes the
severity
of the tics.

The most severe tics are found in people with Tourette's Syndrome.
This is usually a life-long problem involving many different kinds of
tics. Fortunately, it is very rare - about 5 in 10,000
people. They may have
tics involving complex movements, such as touching things or full body
motions.
Most characteristics of Tourette's are vocal tics, including a variety
of
clicks, grunts, barks, snorts, and coughs. About 10% of
Tourette's
sufferers have what is called coprolalia
(Greek for "shit-talk"), which is the involuntary
shouting
of obscenities. Often the obscenities are situational, so that
when
the person is dealing with a woman, they may be unable to restrain
themselves
from shouting "bitch!" or when dealing with an African American person,
they
may
shout "nigger!" That might seem amusing, until you put yourself
in
their shoes. They are likely not sexist or racist - they just
can't stop themselves.

Separation Anxiety

Separation anxiety is a very common problem among children,
especially younger ones. It is found in about 4% of kids.
The problem is
excessive anxiety about separation from the child's parents, other
family members, or even their home. When separated, they become
withdrawn and
depressed and may have difficulty concentrating. They often
develop other fears, anxiety about death, and nightmares. Of
course, some separation
anxiety is a normal part of childhood, so this can be a bit of a
subjective
call.

Separation anxiety usually occurs in tight, loving families.
It often
begins with some kind of life stress, such as moving to a new home or
town,
starting at a new school, or the death of a pet or relative.
Fortunately,
for most children, it ends sometime in adolescence if not earlier.

Conduct disorder

Children or adolescents with conduct disorder behave
aggressively by fighting, bullying, intimidating, physically
assaulting, sexually coercing, and/or being cruel to people or animals.
Vandalism with deliberate destruction of property, for example, setting
fires or smashing windows, is common, as
are theft; truancy; and early tobacco, alcohol, and substance use and
abuse;
and precocious sexual activity. Girls with a conduct disorder are prone
to
running away from home and may become involved in prostitution. The
behavior
interferes with performance at school or work, so that individuals with
this
disorder rarely perform at the level predicted by their IQ or age.
Their
relationships with peers and adults are often poor. They have higher
injury
rates and are prone to school expulsion and problems with the law.
Sexually
transmitted diseases are common. If they have been removed from home,
they
may have difficulty staying in an adoptive or foster family or group
home,
and this may further complicate their development. Rates of depression,
suicidal
thoughts, suicide attempts, and suicide itself are all higher in
children
diagnosed with a conduct disorder (Shaffer et al., 1996b).

The etiology of conduct disorder is not fully known. Studies of
twins and adopted children suggest that conduct disorder has both
biological (including
genetic) and psychosocial components (Hendren & Mullen, 1997).
Social
risk factors for conduct disorder include early maternal rejection,
separation
from parents with no adequate alternative caregiver available, early
institutionalization,
family neglect, abuse or violence, parents’ psychiatric illness,
parental
marital discord, large family size, crowding, and poverty (Loeber &
Stouthamer-Loeber,
1986).... Physical risk factors for conduct disorder include
neurological
damage caused by birth complications or low birthweight,
attention-deficit/hyperactivity disorder, fearlessness and
stimulation-seeking behavior, learning impairments, autonomic
underarousal, and insensitivity to physical pain and punishment. A
child with both social deprivation and any of these neurological
conditions is most susceptible to conduct disorder (Raine et al.,
1998)....

Studies have shown a correlation between the behavior and
attributes of 3-year-olds and the aggressive behavior of these children
at ages 11 to
13 (Raine et al., 1998).

Among children from 9 to 17, we find between 1 and 4 percent showing
evidence of conduct disorder, and the problem being worse in the
cities. Between 25 and 50% of these children are believed to
develop into antisocial adults.

Treatment of children with conduct disorder tends to focus on making
their
family lives happier and more consistent. If the parents or other
caretakers
are responsive, there are programs that teach them how to use rewards
and
punishments more effectively. For many of these kids, it is a
matter
of trying to find a home for them at all! Medications have not
been
found to help.